• 한국신뢰성학회지:신뢰성응용연구
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• 제16권3호
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• pp.224-230
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• 2016

Purpose: Military maintenance involves corrective and preventive actions carried out to keep a system in or restore it to a predetermined condition. This research develops an optimal maintenance cycle for aviation oil testing equipment with acceptable reliability level and minimum maintenance cost. Methods: The optimal maintenance policy in this research aims to satisfy the desired reliability level at the lowest cost. We assume that the failure process of equipment follows the power law non-homogeneous Poisson process model and the maintenance system is a minimal repair policy. Estimation and other statistical procedures (trend test and goodness of fit test) are given for this model. Results: With time varying failure rate, we developed reliability-based maintenance cost optimization model. This model will reduce the ownership cost through adopting a proactive reliability focused maintenance system. Conclusion: Based on the analysis, it is recommended to increase the current maintenance cycle by three times which is 0.5 year to 1.5 years. Because of the system's built-in self-checking features, it is not expected to have any problems of preventative maintenance cycle.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권4호
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• pp.280-286
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• 2016

Purpose: Recently, Jiang defines the tradeoff B life to minimize a sum of life lost by preventive maintenance (PM) and corrective maintenance (CM) contribution parts and sets up an optimal replacement age of age replacement policy as this tradeoff life. In this paper, Jiang's model only considering the known lifetime distribution is extended by assigning different weights to two parts of PM and CM in order to reflect the practical maintenance situations in application. Methods: The new age replacement model is formulated and the meaning of a weight factor is expressed with the implied cost of failure under asymptotic expected cost model and also discussed with one-cycle expected cost criterion. Results: The proposed model is applied to Weibull and lognormal lifetime distributions and optimum PM replacement ages are derived with corresponding implied cost of failure. Conclusion: The new age replacement policy to escape the estimation of cost of failure in classical asymptotic expected cost criterion based on the renewal process is provided.

• 한국국방경영분석학회지
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• 제28권1호
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• pp.97-114
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• 2002

An estimation of economic life for a new weapon system is a critical issue in aquisition process. In general a life cycle cost consists of, development cost, aquisition cost, and maintenance cost. These costs are not identified and obtained in the beginning of the aquisition process. This paper deals with an economic life for KlAl tank which is being deployed recently, using PRICE model. In order to estimate an KlAl economic life, we use equivalent annual cost method which is sum of capital recovering with return and equivalent O&M cost method. This method determines an economic life by minimizing annual investment cost and operation and maintenance cost. In this paper, an aquisition cost of KlAl is obtained from PRICE H and O&M cost from PRICE HL model. We obtained various results depending upon production quantity. An economic life for KlAl is estimated 18 years when 300 tanks are produced.

• 한국건설관리학회논문집
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• 제17권2호
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• pp.31-38
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• 2016

건설사업비 중 건축물의 유지관리비용이 차지하는 비중이 초기투자비만큼이나 상당하며 국내의 경우 건설공사의 생애주기비용(LCC)관점에서 설계VE검토 업무를 시행하고 있다. 건설산업의 정보화와 고도화 급속히 진행됨에 따라 BIM에 대한 관심이 고조되고 있다. 2012년부터 조달청은 500억원 이상인 공공공사에 BIM적용을 의무화를 시작으로 2016년부터 조달청이 발주하는 모든 공공공사에 BIM적용이 의무화된다. 건축설계의 패러다임이 2D방식에서 3D, 데이터관리 관점의 BIM으로의 전환이 정책적으로 이루어지고 있는 환경에서, LCC측면에서의 BIM활용에 대한 연구는 미흡한 실정이다. 특히, LCC분석 요소 중 하나인 수선교체비 산정을 위한 BIM 소프트웨어는 부재하며 상용화된 BIM저작도구에서 수선교체비 산정을 위한 정보의 전달이 부족하다. 따라서 본 연구에서는 데이터 표준 포맷인 IFC기반 수선교체비 산정을 위한 프로세스를 제안한다. 먼저, 현재 존재하는 수선교체 기준을 분석하고 BIM기반 수선교체비 산정 요구정보를 정의한다. 정의된 요구정보는 각 정보에 해당하는 IFC를 통해 추출되고, BIM기반 수선교체비 산정 요구정보 DB에 저장된다. 이는 외부 DB인 수선교체기준DB와 단가DB와 연계하여 수선교체비를 산정한다. 본 연구가 제시하는 프로세스를 통해 BIM환경에 대응하여 BIM모델을 활용한 수선교체비 산정의 효율화를 기대하며 수선교체비 뿐만 아니라 초기공사비, 에너지비용, 유지관리비용에 이르기까지 향후 LCC분석 요소에 확장하여 적용이 가능할 것이며 BIM기반 LCC분석의 표준화에 기여할 수 있다.

• 한국산학기술학회논문지
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• 제19권12호
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• pp.717-724
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• 2018

사회기반시설물의 노후화에 따른 교량 유지관리비용의 급격한 증가에 대비하기 위해서는 미래 발생 가능한 유지관리비용의 예측이 선행되어야 한다. 이를 위해 본 논문에서는 교량 관리주체의 유지관리 현황 분석을 통해 교량의 관리수준을 파악하고, 이를 생애주기에 따른 목표관리수준과 성능향상 한계 값으로 모델링하였다. 이와 함께 교량 안전점수에 따른 보수보강비용 예측모델, 성능열화모델, 평균개축비용단가, 평균 개축시기로 구성된 기존의 비용 및 성능 예측모델과 연계하여, 교량 유지관리비용 추계분석을 위한 방법론 및 절차를 제안하였다. 제안된 방법의 활용성 검증을 위해 특정 관리주체가 관리하는 교량의 규모, 노후화 정도, 현재 관리현황을 고려하여 미래 유지관리비용 추계 분석을 수행하였다. 연차별로 개별 교량 수준의 안전등급과 유지관리 조치에 따른 비용 추정 결과와 이들을 관리주체 수준으로 합산하여 연차별 평균 안전점수, 안전등급 구성비, 점검진단비용, 보수보강비용, 개축비용을 합리적으로 추정할 수 있다. 향후 목표성능관리수준의 변경에 따른 생애주기 예산의 변화를 추정하여 최적의 관리수준을 제안할 수 있을 것으로 판단된다.

• Industrial Engineering and Management Systems
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• 제15권4호
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• pp.403-431
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• 2016

The objective of this study is to integrate the business, maintenance and production processes of a manufacturing system by incorporating errors. First, the required functions are estimated according to the historical data. The system activities are simulated by Visual SLAM software and the required outputs are obtained. Several outputs including lead times in different dimensions, total cost and production rates are computed through simulation. Finally, data envelopment analysis (DEA) is utilized in order to select the best option between the defined scenarios due to the multi-criteria feature of the problem. This is the first study in which the lead times, cost and production rates are simultaneously considered in the integrated system imposed of business, maintenance and production processes by incorporating errors. In the current study, the major bottlenecks of the system being studied are identified and suggested different strategies to improve the system and make the best decision.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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• pp.224-228
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• 2007

It is focused on a methodology to establish a optimal inspection cycle of electrical facility of railroad Decision method of optimal inspection cycle is a process which establishes maintenance plan for facilities' immanent function as using reliability theory in operation term In order to ensure normal operation in a given condition, the decision method is logical for selecting effective maintenance plan to consider characteristic of system In estimation of failure rate, critical facility is selected firstly. After that, proper distribution function on each facility is decided to investigate distribution function for extraction of failure rate. Next, cost produced by the case that facility's failure is occurred is surveyed. Finally, maintenance method developed until now is investigated, before suitable model for the facility applying maintenance method is developed, and that maintenance decision is made. Therefore, this process is the method to find optimal inspection cycle for reasonable cost and effective reliability on facility.

• 한국산업융합학회 논문집
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• 제26권5호
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• pp.855-866
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• 2023

With the rapid advancement and sophistication of defense weapon systems, the government, military, and the defense industry have conducted various innovative attempts to improve the efficiency of post-logistics support(PLS). The Ministry of Defense has mandated RAM-C(Reliability, Availability, and Maintainability-Cost) analysis as a requirement according to revised Total Life Cycle System Management Code of Practice in May 2022. Especially, for the project budget forecast of new PBL(Performance Based Logistics) business contacts, RAM-C is recognized as an obligatory factor. However, relevant entities have not officially provided guidelines or manuals for RAM-C analysis, and each defense contractor conducts RAM-C analysis with different standards and methods to win PBL-related business contract. Hence, this study aims to contribute to the generalization of the analysis procedure by presenting a cost analysis case based on RAM-C for the supply of military depot maintenance PBL project. This study presents formulas and procedures to determine requirements of military depot maintenance PBL project for repair parts supply. Moreover, a sensitivity analysis was conducted to find the optimal cost/utilization ratio. During the process, a correlation was found between supply delay and total cost of ownership as well as between cost variability and utilization rate. The analysis results are expected to provide an important basis for the conceptualization of the cost analysis for the supply of military depot maintenance PBL project and are capable of proposing the optimal utilization rate in relation to cost.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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• pp.87-88
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• 2016

In order to assess the design value of engineering work from the point of view of LCC (Life Cycle Cost) in Korea, it is mandatory for all construction works that the total construction costs are over 10 billion won. The LCC includes initial construction costs, maintenance & operation costs, energy costs, end-of-life costs, and so on. Among these, the portion for maintenance & operation costs for a building is sizeable, as compared to the initial construction costs. Furthermore, the paradigm for construction industry has rapidly shifted from 2D to BIM, which includes design planning and data management. However, the study of BIM-based LCC analysis is not adequate today, even though all domestic construction projects ordered by the Public Procurement Service have to adopt BIM. Therefore, this study suggests a methodology of BIM-based LCC analysis that is particularly focused on repair and replacement (R&R) cost. For this purpose, we defined requirements of calculating R&R cost and extracted X from the relevant IFC data. Thereafter, we input them to the ontology of calculating the initial construction costs to obtain an objective output. Finally, in order to automatically calculate R&R cost, mapping with R&R criteria was performed. We expect that our methodology will contribute to more efficiently calculate R&R cost and, furthermore, that this methodology will be applicable to all range of total LCC. Thus, the proposed process of automatic BIM-based LCC analysis will contribute to making LCC analysis more fast and accurate than it is at present.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.823-830
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• 2022

The risk of project execution increases due to the enlargement and complexity of Engineering, Procurement, and Construction (EPC) plant projects. In the fourth industrial revolution era, there is an increasing need to utilize a large amount of data generated during project execution. The design is a key element for the success of the EPC plant project. Although the design cost is about 5% of the total EPC project cost, it is a critical process that affects the entire subsequent process, such as construction, installation, and operation & maintenance (O&M). This study aims to develop a system using machine-learning (ML) techniques to predict risks and support decision-making based on big data generated in an EPC project's design and construction stages. As a result, three main modules were developed: (M1) the design cost estimation module, (M2) the design error check module, and (M3) the change order forecasting module. M1 estimated design cost based on project data such as contract amount, construction period, total design cost, and man-hour (M/H). M2 and M3 are applications for predicting the severity of schedule delay and cost over-run due to design errors and change orders through unstructured text data extracted from engineering documents. A validation test was performed through a case study to verify the model applied to each module. It is expected to improve the risk response capability of EPC contractors in the design and construction stage through this study.